First Measurements of Resonance Driving Terms in the SPS

It has been recently shown that a refined Fourier analysis of tracking data can be used to obtain the resonance driving terms and even the non-linear one-turn map that represents the linear accelera tor structure with all non-linearities arising from magnetic imperfections and correction elements. In principle the same information should be obtainable from pick-up data of kicked beams.In ca se these resonance terms can be determined with high enough precision one can evaluate and compare different settings of non-linear elements and one may be able to correct resonances giventhat the corresponding correctors are available in the accelerator at proper locations. This study is important in particular for the LHC,as the performance of this machine will depend on various non-linear correction systems, which will have to be adjusted using on-line measurements. This year's goal is to establish the feasibility of the method. More detailed studies are foreseen for next year.